List of top Physics Questions on Nuclei asked in CBSE CLASS XII

Draw the graph showing the variation of scattered particles detected (\( N \)) with the scattering angle (\( \theta \)) in the Geiger-Marsden experiment. Write two conclusions that you can draw from this graph. Obtain the expression for the distance of closest approach in this experiment.
Differentiate between nuclear fission and fusion.

From the relation \(R = R_0A^{\frac{1}{3}}\), where \(R_0\) is a constant and A is the mass number of a nucleus, show that the nuclear matter density is nearly constant (i.e. independent of A).

Calculate the height of the potential barrier for a head on collision of two deuterons.(HINT:The height of the potential barrier is given by the Coulomb repulsion between the two deuterons when they just touch each other. Assume that they can be taken as hard spheres of radius 2.0 fm.)

How long can an electric lamp of 100W be kept glowing by fusion of 2.0 kg of deuterium? Take the fusion reaction as
\(^{2}_{1}H + ^{2}_{1}H →^{3}_{1}He + n + 3.27 \space MeV\)

The fission properties of \( ^{239}_{ 94} Pu\) are very similar to those of \(^{235}_{92} U\). The average energy released per fission is 180 MeV. How much energy, in MeV, is released if all the atoms in 1 kg of pure. \( ^{239}_{ 94} Pu\) undergo fission?

Suppose we think of fission of a \(^{56}_{26}Fe\) nucleus into two equal fragments, \(^{28}_{13} Al.\) Is the fission energetically possible? Argue by working out Q of the process. Given \(m\)(\(^{56}_{26}Fe\)) = 55.93494 u and \(m\)(\(^{28}_{13} Al\)) = 27.98191 u.

The Q value of a nuclear reaction A + b → C + d is defined by
Q = [mA+mb–mC–md]c2 
where the masses refer to the respective nuclei. Determine from the given data the Q-value of the following reactions and state whether the reactions are exothermic or endothermic.
(i) \(^{1}_{ 1} H + ^{3} _{1}H → ^{2}_{1} H + ^{2}_{1} H\)
(ii) \(^{12}_{6} C + ^{12}_{6} C → ^{12}_{10} Ne + ^{4}_{2} He\)
Atomic masses are given to be
\(m (^{2}_{ 1} H)\) = 2.014102 u
\(m (^{3}_{1} H) \)= 3.016049 u
\(m (^{12}_{ 6} C) \)= 12.000000 u
\(m (^{20}_{10} Ne)\) = 19.992439 u

Obtain approximately the ratio of the nuclear radii of the gold isotope \(^{197}_{ 79} Au \) and the silver isotope \(^{107}_{ 47} Ag\).

A given coin has a mass of 3.0 g. Calculate the nuclear energy that would be required to separate all the neutrons and protons from each other. For simplicity assume that the coin is entirely made of \(^{63}_{ 29}Cu\) atoms (of mass 62.92960 u).

Obtain the binding energy of the nuclei \(^{56}_{26}Fe\) and \( ^{209} _{83} Bi\) in units of MeV from the following data: \(m\) (\(^{56}_{26}Fe\)) = 55.934939 u, \(m\) (\( ^{209} _{83} Bi\)) = 208.980388 u

Obtain the binding energy (in MeV) of a nitrogen nucleus. \((^{14}_{7}N)\) , given m \((^{14}_{7}N)\) = 14.00307 u